0 

0.  E.  S.  Library.  Cop.  2.  ■  LI  ; 

CONNECTICUT  n^- 1 

mmmmi  experimeit  station 

NEW    HAVEN,    CONN. 


BULLETIN   169,   NOVEMBER,   1911. 


ENTOMOLOGICAL  SERIES,   No.   i6. 


The  Leopard  Moth 


Fig.  I.     Female  Leopard  Moth.     Natural  size. 

CONTENTS. 

Page 

Appearance  of  Infested  Trees 3 

This  Insect  a  Pest  in  Europe 4 

Occurrence  in  other  Countries 5 

History  of  its  Spread  in  America   5 

Distribution  and  Spread  in  Connecticut 8 

Description 9 

Life  History  and  Injury 10 

Natural  Enemies  and  Checks 14 

Remedial  Treatment. 15 

Bibliography 20 

Summary 24 

The  Bulletins  o£  this  Station  are  mailed  free  to  citizens  of  Con- 
necticut who  apply  for  them,  and  to  others  as  far  as  the  editions 
permit. 


CONNECTICUT  A&RICULTURAL  EXPERIMENT  STATION, 


BOARD  OF  CONTROL. 

His  Excellency,  Simeon  E.  Baldwin,  ex-officio,  President. 

Prof.  H.  W.  Conn,  Vice  President Middletown 

George   A.   Hopson,   Secretary Wallingf ord 

E.  H.  Jenkins,  Director  and  Treasurer New  Haven 

J.  W.  Alsop Avon 

Wilson  H.  Lee Orange 

Frank  H.  Stadtmueller Elmwood 

James  H.  Webb Hamden 


Administration. 


Chemistry. 

Analytical  Laboratory. 


STATION    STAFF. 

E.  H.  Jenkins,  Ph.D.,  Director  and  Treasurer. 
Miss  V.  E.  Cole,  Librarian  and  Stenographer. 
.Miss  L.  M.  Brautlecht,  Bookkeeper  and  Stenographer. 
William  Veitch,  In  Charge  of  Buildings  and  Grounds. 

John  Phillips  Street,  M.S.,  Chemist  in  Charge. 

E.  Monroe  Bailey,  Ph.D.,  C.  B.  Morrison,  B.S., 

R.  B.  Roe,  A.B.,  C.  E.  Shepard,  Assistants. 

Hugo  Lange,  Laboratory  Helper. 

V.  L.  Churchill,  Sampling  Agent. 


Proteid  Research. 


T.  B.  Osborne,  Ph.D.,   Chemist  in  Charge. 
Miss  E.  L.  Ferry,  A.B.,  Assistant. 
Miss  Luva  Francis,  Stenographer. 


Botany. 


G.  P.  Clinton,  S.D.,  Botanist. 

E.  M.  Stoddard,  B.S.,  Assistant. 

Miss  M.  H,  Jagger,  Seed  Analyst. 

Miss  E.  B.  Whittlesey,  Herbarium  Assistant. 


Entomology. 


W.  E.   Britton,  Ph.D.,  Entomologist;  also  State 

Entomologist. 
B.  H.  Walden,  B.Agr.,  D.  J.  Caffrey,  B.S.,  Assistants. 
Miss  E.  B.  Whittlesey,  Stenographer. 


Forestry. 


Samuel  N.  Spring,  M.F.,  Forester;  also  State 

Forester  and  State  Forest  Fire  Warden. 
W.  O.  Filley,  Assistant  State  Forester. 
Miss  E.  L.  Avery,  Stenographer. 


Plant  Breeding. 


H.  K.  Hayes,  M.S.,  Plant  Breeder. 
C.  D.  Hubbell,  Assistant. 


THE  LEOPARD  MOTH. 

Zeitzera  pyrina  Linn.  (=  ccsculi  Linn.) 

BY 

W.  E.  Britton,  State  Entomologist, 

AND 

G.  A.  Cromie,  Superintendent  of  Trees 
in  the  City  of  New  Haven. 


Appearance  of  Infested'  Trees. 

Many  of  the  magnificent  elms  that  have  stood  as  landmarks 
on  the  streets  and  in  the  central  parks  of  New  Haven  and  other 
coastwise  cities  of  Connecticut  for  over  a  century  are  dying  with 
little  outward  apparent  cause.  And  not  only  are  the  veterans 
being  destroyed,  but  trees  of  all  ages  suffer  where  apparently 
receiving  sufficient  food  and  moisture.  Dead  branches  may  be 
seen  in  numbers,  standing  above  the  leafy  masses  in  the  tree-tops. 
Each  storm  brings  down  numbers  of  branches,  many  of  them  in 
full  leaf,  and  if  the  broken  ends  are  examined,  one  will  notice 
that  just  underneath  the  bark  the  branch  has  been  girdled.  This 
is  the  work  of  an  insect  that  has  only  within  the  last  few  years 
reached  Connecticut,  but  which  has  already  proved  itself  our 
most  serious  insect  enemy  of  shade  trees, — the  leopard  moth. 

Trees  recently  infested  show  small  twigs  broken  over  and 
wilted,  the  leaves  on  the  ends  of  occasional  brandies  turn  yellow 
and  in  a  few  weeks  drop.  Trees  in  a  later  stage  show  a  mass 
of  dead  upper  branches,  as  is  shown  on  Plate  I,  while  from  the 
trunk  and  larger  limbs  sprouts  or  suckers  appear.  Here  and 
there  branches  are  seen  with  comparatively  few,  small,  sickly 
leaves.  Yet  when  the  tree  is  cut  down  the  trunk  and  larger  limbs 
have  the  appearance  of  perfect  health. 

Since  the  larva  bores  largely  in  the  sapwood  and  cambium, 
the  damage  done  by  it  is  unusually  severe,  the  work  of  one  insect 
often  being  sufficient  to  kill  a  small  tree.  Remaining  in  the  wood 
during  the  greater  part  of  its  life,  it  is  rarely  seen  by  the  casual 
observer,  and  for  the  same  reason  no  general  and  convenient 


4     "   CONNECTICUT    EXPERIMENT    STATION,    BULLETIN    NO.    169. 

methods  of  controlling  it  are  available,  as  in  the  case  of  insects 
which  eat  the  foliage.  It  does  not  confine  its  attacks  to  elms, 
but  is  a  Yery  general  feeder,  being  found  to  some  extent  on  nearly 
all  our  deciduous  trees  and  larger  shrubs.  Like  many  other 
insect  pests  that  have  at  various  times  become  unusually  destruc- 
tive, this  leopard  moth  is  not  a  native  of  this  country,  but  was 
introduced  here  probably  from  Europe.  The  number  of  dead 
branches  caused  by  it  not  only  threatens  the  life  of  the  tree,  but 
falling  from  the  height  to  which  some  of  our  large  trees  have 
grown,  are  a  source  of  great  danger  to  property  and  to  persons 
passing  beneath  them.  In  Newark,  N.  J.,  scarcely  a  large  tree 
of  species  susceptible  to  attack  stands  to-day,  uninjured  by  this 
pest,  while  numbers  of  young  elms  recently  planted  are  being 
deformed. 

In  Central  Park,  New  York  City,  Dr.  Southwick  ''has  removed 
hundreds  of  loads  of  branches  killed  by  this  insect,"  while  in 
Cambridge,  Mass.,  numbers  of  old  elms  have  already  been 
removed  from  this  cause. 

In  New  Haven  the  damage  is  especially  severe  in  the  older 
sections  of  the  city,  within  a  radius  of  one  mile  from  the  City 
Hall.  On  Central,  Wooster  and  Broadway  Greens  most  of  the 
older  trees  have  either  been  removed  or  are  badly  mutilated  by 
the  removal  of  the  dead  wood.  In  other  parts  of  the  city  the 
insect  is  present,  but  severe  damage  can  be  found  only  in  occa- 
sional groups  of  trees.  Because  the  female  moth  is  a  poor  flyer, 
a  tree  (or  a  group  of  trees)  is  liable  to  be  the  home  of  succeed- 
ing generations  as  long  as  portions  of  it  remain  alive,  while 
trees  only  a  short  distance  away  are  often  free  from  the  pest. 
The  trees  of  New  Haven  are  at  present  especially  liable  to  injury 
because  they  are  large  and  in  long,  close  rows,  with  interlacing 
branches,  and  of  species  readily  attacked. 

This  Insect  a  Pest  in  Europe. 

Though  apparently  the  leopard  moth  is  less  serious  as  a  pest 
of  shade  trees  in  Europe  than  in  this  country,  it  nevertheless 
does  considerable  damage.  Theobald^^  states  that  it  attacks 
chiefly  the  cherry,  apple,  pear  and  plum  in  England,  but  that  he 
has  also  seen  young  walnut  trees  killed  by  it,  and  furthermore 
that  "it  has  been  decidedly  on  the  increase  in  apple  trees  during 
the  last  few  years."     He  also  remarks  that  the  leopard  moth  has 


THE   LEOPARD    MOTH.  5 

long  been  known  as  a  borer  into  the  trunks  of  various  trees  in 
England  and  all  over  Europe.  In  addition  to  the  trees  just 
named,  Miss  Ormerod^^  mentions  ash,  beech,  birch,  elm,  holly, 
lime,  oak  and  horse  chestnut.  Gillanders^^  includes  the  haw- 
thorn and  sycamore  among  the  trees  attacked  and  injured  in 
England.  Rev.  J.  G.  Wood^^  many  years  ago  wrote  that  though 
the  leopard  moth  infested  fruit  trees  in  England,  it  seemed  to 
do  little  if  any  harm  to  them.  Eckstein^^  writes  of  the  leopard 
moth  as  also  attacking  syringa,  willow,  maple,  mountain  ash  and 
mistletoe  in  Germany,  in  addition  to  the  food  plants  already 
mentioned  here.  Kollar^*  states  that  in  the  neighborhood  of 
Vienna  the  leopard  moth  injures  the  trunks  of  elm,  walnut,  pear 
and  apple  trees.  To  this  list,  according  to  Judeich-Nitsche^^, 
may  be  added  Hnden,  poplar,  cytisus,  alder,  pomegranate  tree, 
spindle  tree  (Euonymus)  and  pine. 

The  leopard  moth  is  figured  in  Atlas  d'Entomologie^^  Fores- 
tiere,  plate  29,  by  E.  Henry. 

The  foregoing  references  have  been  cited  here  to  show  that  the 
insect  is  a  recognized  pest  of  trees  in  Europe,  although  Dr.  L.  O. 
Howard,  who  has  made  several  trips  through  Europe,  states  in  a 
letter  that  the  insect  does  not  seem  to  be  especially  destructive 
in  any  part  of  Europe  which  he  has  visited. 

Occurrence  in  Otther  Countries. 

Though  the  leopard  moth  is  found  throughout  Central  and 
Southern  Europe,  according  to  the  Bureau  of  Entomology^^  it 
also  occurs  in  Asia  Minor,  Northern  Morocco,  Algeria  and  South- 
western Africa.  Mr.  South^^  states  that  it  is  also  present  in 
Corea  and  Japan. 

According  to  P.  Lesne,^^  this  insect  is  the  worst  pest  of  the 
cork  oak  in  Algeria,  though  after  three  years  work  he  claims^* 
to  have  brought  it  under  control  by  the  use  of  carbon  disulphide 
squirted  into  the  galleries,  or  better  yet,  placed  in  gelatine  cap- 
sules small  enough  to  be  inserted  in  the  burrows.  The  moisture 
in  the  wood  dissolves  the  gelatine  in  twenty-four  hours,  and  the 
fumes  then  kill  the  borers. 

History  of  its  Spread  in  America. 

The  leopard  moth  occurs  in  Europe,  and  is  believed  to  have 
been  introduced  from  there  into  the  United  States,  though  the 


6         CONNECTICUT    EXPERIMENT    STATION^    BULLETIN    NO.    169. 

date  of  its  introduction  is  uncertain.  The  species  is  included  by 
Walker  in  his  list  of  Lepidoptera  in  the  British  Museum/^  as 
occurring  in  North  America,  and  by  John  G.  Morris  in  his 
Synopsis  of  the  Described  Lepidotera  of  North  America,^  with 
a  brief  description,  and  the  locality  given  as  "North  America." 
Two  years  later  (1864)  the  late  Professor  A.  S.  Packard,  in  his 
Synopsis  of  the  Bombycidae  of  the  United  States^  also  includes 
Zeuzera  pyrina  with  the  same  statement  as  occurs  in  the  Morris 
catalogue,  from  which  it  may  have  been  copied.  Zeuzera  pyrina 
may  also  be  found  in  the  list  (page  10)  of  North  American 
Lepidoptera,  published  by  the  Brooklyn  Entomological  Society 
in  1881. 

Professor  John  B.  Smith,^*  however,  doubts  the  identity  of 
the  species  listed  as  Z.  pyrina  in  Walker's  catalogue,  which 
Morris,  and  probably  Packard,  had  followed.  Smith  visited  the 
British  Museum  and  was  unable  to  find  any  specimens  or  rec- 
ords^^  there  to  warrant  Walker's  citation  that  Z.  pyrina  occurred 
in  North  America  at  the  time  his  catalogue  was  issued. 

The  first  definite  record  of  the  occurrence  of  the  leopard  moth 
in  America  is  a  short  note  by  Mr.  Jacob  Doll  in  Papilio,^  which 
states :  "A  fine  example  of  this  well-known  European  species  was 
taken  in  a  spider's  web  in  Hoboken,  N.  J.,  in  June,  last,  by  Mr. 
Schmitz.  It  was  alive  and  was  endeavoring  to  escape  from  the 
web.  The  specimen  is  now  in  the  collection  of  Mr.  B.  Neu- 
moegen."     This  was  written  in  1882,  and  the  moth  taken  in  1881. 

Entomological  News  for  March,  1904,*®  states  that  this  speci- 
men was  a  female,  and  was  captured  in- 1879  instead  of  1881. 
Be  that  as  it  may,  the  destructive  work  of  the  moth  was  observed 
in  Central  Park,  New  York  City,  in  1884,  by  Dr.  E.  B.  Southwick, 
and  in  1887  at  Newark  and  in  1889  at  Arlington  and  Orange, 
New  Jersey.  In  1894,  Dr.  Southwick  pronounced  it  one  of  the 
worst  insect  pests  attacking  shade  trees.^"^ 

In  1894,  Smith  stated^^  that  Col.  Nicholas  Pike  reported  that 
the  leopard  moth  occurred  in  Connecticut.  It  was  soon  noticed 
in  cities  near  New  York,  though  spreading  much  faster  toward 
the  northeast  along  the  coast  than  in  any  other  direction.  In 
1905,  Dr.  Felt*"^  reported  the  pest  at  Kensico,  N.  Y.,  a  point 
twenty-five  miles  north  of  New  York  City.  The  earliest  Massa- 
chusetts record  that  we  can  find  is  that  of  a  male  taken  by  Mr. 
C.  A.  Frost^*^  at  Medford,  July  ist,  1903.     In  1907,  Professors 


THE   LEOPARD    MOTH.  7 

C.  H.  and  H.  T.  Fernald*^  called  attention  to  the  presence  of  the 
insect  in  the  vicinity  of  Boston.  In  1909  the  senior  author 
learned  of  its  great  destructiveness  to  the  trees  of  Cambridge. 
Mr.  E.  H.  Armstrong  has  observed  its  work  at  Taunton,  Fall 
River  and  New  Bedford,  and  Chapman^^  reports  its  presence  at 
Concord,  Lowell  and  Lawrence,  as  well  as  at  many  other  places 


Fig.  2.  Shaded  area  shows  present  distribution  of  the  leopard  moth  in 
the  northeastern  states.  Cape  Cod  may  also  be  infested  but  we  have  no 
records  to  show  it. 


nearer  Boston.  Mr.  Armstrong  is  authority  for  the  report  that 
the  insect  occurs  at  Providence,  Newport,  Westerly  and  East 
Greenwich,  in  Rhode  Island. 

The  leopard  moth  is  reported  by  Professor  Smith^^  as  occur- 
ring as  far  south  as  Long  Branch,  N.  J.,  and  Mr.  Bartlett  has 
seen  it  at  Asbury.  At  the  present  time,  as  is  shown  by  the  map. 
Fig.  2,  the  insect  occurs  from  Asbury,  N.  J.,  at  least  to  the 


8         CONNECTICUT    EXPERIMENT    STATION,    BULLETIN    NO.    169. 

vicinity  of  Lawrence,  Mass.,  and  in  nearly  every  city  along  the 
coast,  between  these  points,  much  damage  has  been  done  by  it  to 
shade  trees.  AVe  have  no  records  of  the  occurrence  of  the  insect 
at  points  more  than  twenty-five  miles  inland.  It  is  difficult  to 
explain  why  it  should  spread  so  much  more  rapidly  toward  the 
northw^est,  along  the  coast,  than  in  any  other  direction.  Chap- 
man questions^^  whether  the  infestation  around  Boston  may  not 
have  resulted  from  a  separate  and  later  importation. 

Distribution  and  Spread  in  Connecticut. 

Though,  as  already  stated,  the  leopard  moth  was  reported  to 
have  reached  Connecticut  by  1894,-^  the  first  definite  record  that 
has  come  to  our  notice  is  that  of  Mr.  H.  M.  Russell,  now  of  the 
Bureau  of  Entomology,  who  formerly  lived  in  Bridgeport,  Conn. 
]\Ir.  Russell  collected  specimens  of  the  leopard  moth  at  Bridge- 
port in  1901.^^ 

The  first  Connecticut  specimen  in  the  collection  of  this  station 
was  taken  in  New  Haven,  July  ist,  1907,  by  Professor  H.  W. 
Foote  of  Yale  University.  Since  then  a  number  of  specimens, 
chiefly  males,  have  been  taken  around  electric  lights.  Mr.  A.  B. 
Champlain,  a  former  assistant  in  entomology  at  this  station, 
collected  and  observed  the  males  during  1910  and  191 1,  at  several 
arc  lights,  including  those  near  the  station  on  Prospect  street. 

The  photograph  on  Plate  I  was  taken  on  the  New  Haven 
Green  in  1908,  and  shows  that  the  pest  had  then  been  at  work 
for  some  time,  as  is  evidenced  by  the  dead  terminal  branches. 

Mr.  E.  H.  Armstrong  of  the  Providence  Forestry  Company, 
Inc.,  has  informed  the  senior  author  that  he  has  observed  the 
work  of  the  leopard  moth  in  New  Haven,  New  London,  Mystic 
and  Stonington  and  that  with  the  exception  of  Cambridge,  Mass., 
he  considers  New  Haven  the  worst  infested  spot  that  has  come 
under  his  notice. 

Mr.  F.  A.  Bartlett  of  the  H.  L.  Frost  &  Bartlett  Company 
states  in  a  letter  that  he  has  observed  the  work  of  the  insect  in 
practically  every  town  and  city  along  the  Connecticut  coast  this 
year,  and  that  it  has  been  especially  serious  at  Bridgeport  and 
less  so  at  Stamford  and  South  Norwalk.  He  also  saw  a  little 
of  its  work  at  Danbury,  which  is  about  twenty-five  miles  inland. 

Mr.  D.  J.  Caffrey,  assistant  in  charge  of  the  gypsy  moth  work, 
observed,  in  191 1,  many  trees  showing  the  characteristic  leopard 
moth  injury  at  Wallingford,  about  twelve  miles  from  the  coast. 


THE    LEOPARD    MOTH.  9 

In  September,  1910,  the  leopard  moth  was  found  infesting 
young  apple  trees  in  a  nursery  at  New  Canaan,  Conn.,  the  adult 
insect  was  reared  from  the  larva,  and  a  short  account  was  pub- 
lished in  the  Journal  of  Economic  Entomology*^^  for  June,  191 1. 
This  locality  was  less  than  ten  miles  from  the  coast.  The  insect 
was  found  again  in  the  same  field  in  September,  191 1. 

Description. 

Adults. — Wing  expanse  from  two  and  one-half  to  three  inches  in  the 
female  and  about  one  and  three-fourths  inches  in  the  male.  Wings  dirty 
white  and  semitransparent,  with  a  yellow  or  brownish  front  margin  to  the 
fore  wings  and  the  same  color  extending  along  the  principal  veins.  The 
wings  are  marked  with  metallic  blue  dots,  as  shown  in  the  accompanying 
illustrations,  Figure  i,  and  Plate  VIII,  a.     The  markings  are  much  more 


Fig.  3.     Leopard  moth  caterpillar.     Dor- 
sal and  lateral  views,  natural  size. 


Fig.  4.     Pupa, 
natural  size. 


pronounced  in  the  female  than  in  the  male,  which  sometimes  has  ver3^  faint 
dots.  Color  much  brighter  in  the  female.  Thorax  white  or  yellow 
dorsally,  with  six  blue-black  spots,  three  in  a  row  on  each  side.  Ventral 
side,  black;  abdomen,  black,  with  more  or  less  whitish  pubescence,  and 
the  female  has  an  extensile  three-jointed  ovipositor,  by  means  of  which 
eggs  are  laid  under  the  edges  of  bark;  legs,  black;  the  second  and  third 
pairs  of  femora  bearing  whitish  woolly  hairs.  The  female  has  thread-like 
and  the  male  feathery  antennae.  The  female  is  shown  in  Figure  i,  and 
both  sexes  on  Plate  VIII,  a. 

Egg. — The  eggs  are  about  the  size  of  a  pinhead,  or  one-sixteenth  of 
an  inch  long,  oval,  somewhat  pointed,  and  salmon  or  orange-yellow  in 
color.  They  are  usually  laid  singly  or  in  groups  of  two,  three,  or  four 
each.     Shown  on  Plate  VIII,  b. 

Larva. — Length  about  two  and  one-fourth  inches,  dirty  white,  dull 
yellow,  or  flesh-colored,  marked  with  dark  brown  or  black  tubercles,  each 
bearing  a  short  bristle.  The  fourth  to  the  tenth  segments  inclusive  bear 
two  pairs  of  tubercles,  the  front  pair  being  closer  together  than  the  rear 


lO      CONNECTICUT    EXPERIMENT    STATION,    BULLETIN    NO.    169. 

pair.  The  second,  third,  eleventh  and  twelfth  segments  have  smaller 
tubercles  arranged  more  nearly  in  transverse  rows.  Laterally,  there  is 
a  row  of  brown  tubercles  just  above  and  another  row  just  below  the 
spiracles.  A  second  row  of  smaller  tubercles  may  be  seen  on  the  bases 
of  the  legs  and  pro-legs.  The  large  cervical  shield  and  smaller  anal 
shield  are  dark  brown.  Head,  dark  brown,  with  upper  part  of  front 
lighter.  Legs,  light  brown.  The  larva  is  shown  in  Figure  3,  and  on 
Plate  VIII,  c. 

Pupa. — About  one  and  one-half  inches  long,  scarcely  tapering,  anal 
extremity,  blunt ;  dark  brown  in  color.  On  the  proximal  and  distal 
margins  of  each  abdominal  segment  there  is  dorsally  a  ridge  consisting  of 
a  number  of  short,  black  spines  or  teeth,  pointing  backward.  Similar 
spines  or  hooks,  projecting  forward,  occur  on  the  ventral  surface  of  the 
posterior  segment.     Shown  in  Figure  4. 


Fig.  5.     Head  and  cervical  Fig.  6.     Anal  plate  of  larva, 

shield  of  larva,  much  enlarged.  much  enlarged. 

All  Stages  of  the  leopard  moth  are  shown  in  the  accompany- 
ing illustrations. 

Life  History  and  Injury. 

Just  as  the  manuscript  of  this  bulletin  was  ready  for  the 
printer,  a  publication  on  the  same  subject  by  James  W.  Chap- 
man/^ and  published  by  the  Bussey  Institution  of  Harvard  Uni- 
versity, came  to  hand.  Mr.  Chapman,  by  original  observations, 
has  made  an  important  contribution  to  the  habits  and  life  his- 
tory of  this  insect,  and  we  have,  therefore,  revised  several  par- 
agraphs in  this  bulletin,  to  include  the  chief  results  of  Mr. 
Chapman's  studies. 

The  adult  moths  appear  during  a  period  extending  from  May 
to  September,  according  to  the  circular  issued  by  the  Bureau 
of  Entomology.^^  In  New  Haven,  however,  by  far  the  greater 
number  are  found  during  the  early  part  of  July,  while  specimens 
have  been  secured  during  late  June  and  the  first  week  in  August. 
The  male  is  much  the  smaller,  and  flies  with  ease,  being  attracted 


THE   LEOPARD    MOTH.  II 

by  the  electric  lights.  The  female  has  a  heavy  body,  and  flies 
very  little,  preferring,  if  possible,  to  lay  eggs  on  the  same  tree 
where  she  emerged  from  the  pupa.  For  this  reason,  high  trees, 
isolated,  and  one  hundred  feet  or  more  away  from  others  injured 
by  the  leopard  moth,  may  remain  uriinfested  for  years,  while 
continuous  rows  of  trees  with  branches  touching  are  soon 
infested  throughout. 

The  moths  eat  nothing  and  live  at  the  most  but  a  few  days, 
the  male  dying  immediately  after  copulation,  the  female  as  soon 
as  the  eggs  are  laid.  One  female  captured  by  the  junior  author 
lived  three  days. 

The  eggs  are  inserted  in  crevices  in  the  bark,  or  beneath 
plates  of  bark,  one  to  several  in  a  place,  usually  in  the  higher 
branches  of  the  tree.  They  may,  however,  be  laid  on  larger 
branches  or  on  the  trunks  of  small  trees.  They  are  less  than 
one-sixteenth  of  an  inch  in  length,  oval,  and  yellowish  or  salmon 
colored.  Several  observers,  including  the  junior  author,  have 
found  the  eggs  laid  by  females  in  confinement,  in  several  masses, 
due,  no  doubt,  to  the  unwillingness  of  the  female  to  deposit 
them  sooner  than  necessary  under  unsuitable  conditions.  Num- 
bers of  the  borers,  just  hatched,  were  found,  and  in  every  case 
they  were  working  singly,  usually  just  above  a  bud  or  twig  on 
one  of  the  smaller  branches.  This,  according  to  J.  W.  Chap- 
man,^^  means  that  the  new  larv^  do  not  enter  the  branch  at  the 
place  where  they  hatch,  but  crawl  some  distance  to  the  smaller 
twigs.  Although  this  is  the  rule,  the  junior  author  has  found 
several  which  had  entered  branches  two  to  five  inches  in  diameter, 
taking  advantage  of  crevices  in  the  bark.  Each  female  may 
deposit  from  400  to  800  eggs. 

The  larv3e  hatch  within  a  few  days  (ten  days,  according  to 
Mr.  Walker^^),  being  plentiful  in  the  latter  part  of  July,  and 
immediately  commence  their  destructive  work,  boring  into  the 
branches.  A  careful  examination  of  the  twigs  of  an  infested 
tree  will  show  a  slight  amount  of  the  white,  powdery  sawdust 
expelled  by  each  larva  during  the  first  few  days  after  hatching. 
In  a  few  days  the  character  of  the  expelled  frass  changes  to 
small  cylindrical  pellets,  light  golden  or  brown  in  color. 

Several  experiments  made  by  Mr.  J.  W.  Chapman^^  are  of 
value  in  showing  the  activity  of  the  newly-hatched  larvae.  A 
number  of  these  were  placed  at  the  base  of  a  fresh  lilac  bush 


12       CONNECTICUT    EXPERIMENT    STATION^    BULLETIN    NO.    169. 

and  soon  commenced  to  climb.  On  reaching  the  twigs,  they 
were  at  once  taken  off  and  again  placed  at  the  base,  when  they 
would  immediately  commence  climbing  again.  In  this  way  four 
of  those  making  the  greatest  progress  had  in  four  hours  traveled 
distances  varying  from  twenty-five  to  eighty  feet. 

Other  experiments  showed  that  some  of  the  more  recently 
hatched  larvae  were  able  to  crawl  from  fifty  to  one  hundred 
feet  on  the  ground,  through  grass  and  rubbish,  while  others 
nearly  full-grown  would  move  very  little,  but  would  protect 
themselves  by  spinning  together  small  particles  of  sticks  and  dirt. 

Growth  is  rapid,  and  the  larvse  reach  a  length  of  about  an 
inch  by  the  end  of  the  first  season.  The  general  tendency  is 
for  the  insect  to  w^ork  upward  from  the  hatching  point,  or  from 
any  opening  made  for  expelling  the  frass.  Small  twigs  are 
hollowed  out,  leaving  little  but  a  shell  of  bark,  and  small  branches 
may  be  girdled,  causing  them  to  break  off  during  a  heavy  rain. 
Where  the  young  hatch  in  larger  branches,  the  regular  burrows 
are  often  varied  by  small,  irregular  patches  eaten  out  of  the 
inner  bark.  Branches  too  small,  in  a  dying  condition,  or  other- 
wise unsuitable,  are  vacated,  the  insect  crawling  on  the  outside 
of  the  bark  and  making  a  fresh  entry  on  another  and  usually 
larger  branch.  A  burrow  may  strike  a  knot  or  small  branch, 
when,  after  going  back  several  inches,  the  insect  starts  in  a  new 
direction.  New  outlets  may  be  made,  and  the  use  of  old  ones 
discontinued  from  time  to  time.  These  outlets  are  always  in 
some  protected  situation  on  the  under  side  of  a  branch  or  in  a 
crotch.  They  are  kept  covered  with  a  closely  woven  silk  web, 
this  being  broken  and  remade  each  time  the  frass  is  expelled. 
In  one  case  the  web  was  broken  by  the  junior  author  and 
remade  by  the  insect  five  times  within  an  hour.  This  web  cer- 
tainly helps  to  conceal  the  hole,  and  may  be  used  to  keep  out 
air,  parasites,  ants  and  other  insects.  Unlike  the  galleries  of 
the  sugar  maple  borer,  those  of  the  leopard  moth  are  kept  clear, 
all  frass  being  removed  as  soon  as  a  small  pile  has  accumulated, 
and  cement  sidewalks  under  badly  infested  trees  are  often  lit- 
tered with  the  brownish  pellets  expelled  from  the  burrows. 

During  the  latter  part  of  October  the  larvae  leave  the  outer 
wood  and  bore  slanting  holes  upwards  and  into  the  wood  two 
inches  or  more  from  the  bark,  where  they  remain  in  a  dormant 
stage  over  winter.     Sharps*  cites  Kalendar  to  the  effect  that  the 


PLATE  I. 


Trees  injured  by  leopard  moth  show  dead  terminal  branches.     View  on 
New  Haven  Green.     Photo,  loaned  by  Geo.  Dudley  Seymour. 


PLATE  II, 


a.     White  web  closing  outlet;  wood  cut  away  to  show  burrow.     Twice 

natural  size. 


b.     Branch  girdled  and  broken. 


PLATE  III. 


a.     Bark  removed  to 
show  galleries. 


IM^;  -I"-:, .  *  yp 


M^^^ 


b.     Wound  on  maple  trunk  beginning 
to  heal.     Pupa  case  above. 


c.     Winter  resting  place  of 
larva.     Natural  size. 


PLATE  IV. 


a.     Elm  branch  showing  galleries  of  the  leopard  moth  larva. 


b.     Elm  branch  girdled  by  larva  and  broken. 


PLATE  V. 


Appearance  of  galleries  in  large  branches. 


PLATE  VI. 


^^^1 


Dead  branches  with  bark  removed  to  show  galleries. 


PLATE  VII. 


Male  leopard  moth  reared  from  apple  nursery  stock. 


PLATE  VIII. 


a.     Adult  leopard  moths,  female  at  left.     Natural  size. 


b.     Eggs,  greatly  enlarged. 
Photo,  loaned  by  J.  W.  Chap- 


c.     Larva  in  its  burrow.     Natural  size. 


THE    LEOPARD    MOTH.  1 3 

larva  forms  a  temporary  cocoon  in  which  it  passes  a  winter  sleep 
before  again  feeding  in  the  spring,  but  this  is  not  the  case  in 
Connecticut,  as  Mr.  Cromie  has  taken  numbers  of  naked  larvae 
from  the  branches  during  winter. 

The  boring  is  continued  in  the  same  manner  during  the  next 
summer,  but  the  damage  done  is  now  much  greater,  both  the 
insect  and  the  branches  attacked  being  larger.  Branches  four 
to  eight  inches  in  diameter  may  be  entirely  girdled,  or  large 
patches  of  wood  may  be  eaten  out.  The  wounds  made  the  pre- 
ceding year  now  show  at  their  worst,  the  bark  falling  away,  and 
ugly  ridges  being  made  where  they  have  partially  healed. 

When  fully  grown,  the  larvae  are  about  two  and  one- fourth 
inches  in  length,  and  most  of  them  do  not  enter  the  pupa  state 
until  the  early  part  of  the  succeeding  summer,  when  they  are 
nearly  two  years  old.  The  writers  have  reason  to  believe  that 
some  of  those  hatched  early  change  to  pupae  and  complete  the 
life  cycle  as  those  appearing  latest  during  the  next  year.  How- 
ever, those  passing  the  second  winter  continue  active  boring  in 
the  spring,  changing  to  brownish  pupae  in  May  or  later.  This 
is  done  in  a  small  chamber  within  a  few  inches  of  where  the 
larva  has  previously  cut  its  way  almost  through  the  bark.  It  also 
further  protects  itself,  before  pupating,  by  a  fine  web  placed 
between  itself  and  the  place  of  exit.  In  from  four  to  six  weeks 
the  pupa  cuts  through  the  bark  and,  by  means  of  protuberances 
on  the  abdominal  segments,  wriggles  itself  partially  out  of  the 
hole,  where  it  leaves  the  shell  or  pupa  case  after  it  flies,  as  may 
be  seen  on  Plates  III,  b,  and  VII. 

As  shown  before,  this  insect  attacks  to  some  extent  nearly 
every  tree,  native  or  exotic,  growing  in  this  region,  except  ever- 
greens, so  that  a  full  list  is  not  necessary.  However,  in  New 
Haven  the  American  elm  is  one  of  the  kinds  most  severely 
attacked,  while,  owing  to  its  dark,  plated  bark,  even  on  the 
smaller  branches,  the  insects  in  it  are  very  hard  to  detect.  With 
it,  in  amount  of  injury  done,  may  be  classed  the  silver  maple  and 
the  sycamore  maple.  Other  common  species  often  seriously 
injured  are  ash,  English  elm,  basswood  or  linden,  tulip,  sugar, 
red  and  Norway  maples,  poplar  and  horsechestnut.  The  honey 
locust,  sycamore,  sweet  gum,  and  oak  seem  much  less  liable  to 
attack,  in  many  cases,  in  New  Haven,  remaining  uninjured, 
although  standing  in  rows  with  affected  elms. 


14    connecticut  experiment  station,  bulletin  no.  169. 

Natural  Enemies  and  Checks. 

In  this  country  no  parasites  have  been  recorded  that  hold  the 
leopard  moth  in  check.  In  Europe  a  chalcidid  parasite  of  the 
subfamily  Encyrtinae,  Litomastix  (Copidosoma)  truncatella 
Dalm.,  has  been  reared  by  E.  A.  Fitch.  (Entomological  Magazine, 
Vol.  XVIII,  p.  116.)  This  and  an  ichneumonid,  Schreineria 
zeuzercB  Schrein  (not  Ashm.),  are  mentioned  in  a  letter  to  Mr. 
Cromie  from  the  American  Consul-General  at  Berlin,  the  informa- 
tion being  received  by  him  from  the  Kaiserliche  Biologische 
Anstalt  fiir  Land-und  Forstwirtschaft  in  Dahlem-bei-Steglitz. 
The  former,  L.  truncatella,  is  probably  the  same  as  was  reared  in 
this  country  from  the  cabbage  looper,  Plusia  brassicce  Riley. 
(Rept  of  Ent  U.  S.  Dept.  Agr.  1883,  p.  121.) 

An  examination  of  hundreds  of  the  caterpillars  and  pupae,  as 
well  as  the  burrows  made  by  them,  shows  that  the  leopard  moth 
is  remarkably  free  from  natural  enemies  of  all  kinds.  In  no 
case  was  there  evidence  of  either  parasitic  or  predaceous  insects. 
Dr.  L.  O.  Howard,  who  has  given  some  attention  to  the  subject, 
has  not  found  that  any  effective  parasitic  check  exists  even  in 
Europe,  though  he  has  promised  to  bring  to  America  the  species 
known  to  occur  there.  Mr.  Cromie  found  in  New  Haven  a  cater- 
pillar dead  in  its  burrow  and  full  of  small  maggots,  but  these 
proved  to  be  a  Phorid  fly,  Aphiochceta  nigriceps  Loew.,  which 
probably  did  not  attack  the  borer  until  after  it  had  died  from  some 
other  cause.  This  was  the  only  indication  found  of  an  insect 
being  destroyed  while  in  its  burrow.  All  pupse,  the  stage  gener- 
ally exhibiting  parasitism,  seemed  to  have  developed  properly. 
Undoubtedly  some  check  to  the  insect  must  exist  before  the  bur- 
row is  developed,  because  of  the  small  number  of  burrows  found 
as  compared  with  the  large  number  (several  hundred)  of  eggs, 
laid  by  each  female.  Either  the  female  is  unable  to  deposit  any 
large  number  of  her  eggs  in  proper  situations,  and  they  thus  fail 
to  hatch,  or  the  eggs  themselves  are  largely  eaten  by  the  birds  or 
insects  found  in  cities.  The  writers  have  noticed  that  English 
sparrows  search  for  and  apparently  find  food  on  elms  infested  by 
the  leopard  moth  in  July,  when  the  eggs  should  be  plentiful 
and  the  young  borers  just  hatching,  but  their  prey  might  have 
been  other  insects.  In  many  cases  small  holes,  barely  started  by 
newly  hatched  larvae,  were  found  vacant,  indicating  that  birds 
had  secured  the  insects  before  they  were  able  to  enter  the  wood. 


THE    LEOPARD    MOTH.  15 

As  the  leopard  moth  is  a  pest  chiefly  of  cities  and  towns,  it 
is  thought  that  certain  birds,  especially  woodpeckers,  assist  in 
checking  it,  especially  in  the  country  districts.  The  habits  of  the 
moths  in  flying  about  electric  lights  would  lead  one  to  expect 
that  many  of  them  might  be  eaten  by  bats  and  night-flying  birds. 
It  is  also  believed  that  sparrows  sometimes  may  feed  upon 
the  eggs  or  young  larvae.  Smith  states^^  that  the  leopard  moth 
is  a  serious  pest  only  where  the  English  sparrow  has  driven  away 
the  native  birds. 

No  other  explanation  can  be  given  of  the  scarcity  of  the 
leopard  moth  in  the  country,  adjacent  to  infested  towns,  except 
the  presence  of  insectivorous  birds.  This  tendency  of  the  insect 
to  become  a  pest  only  within  cities  and  towns  is  noted  by  several 
English,  French  and  German  writers,  as  well  as  in  this  country. 
Mr.  James  Walker  of  Newark,  N.  J.,  states  that  infested  elms 
placed  in  a  nursery  outside  the  city  limits  of  Newark  were  rid  of 
the  larvae  by  woodpeckers.  This  coincides  with  a  statement  made 
by  P.  Lesne,'^  who  mentions  having  seen  in  Northern  Algeria 
numerous  woodpecker  holes  ending  in  the  burrows  of  the  leopard 
moth.  While  traveling  from  one  branch  to  another,  a  habit  of 
this  insect,  it  is  exposed  to  the  attacks  of  birds.  Mr.  J.  W.  Chap- 
man^^  also  cites  evidence  of  squirrels  in  the  Boston  parks  chew- 
ing the  smaller  branches  to  secure  the  larvae,  which  they  relish. 

Especially  in  early  summer,  numbers  of  small  girdled  branches 
in  full  leaf  are  broken  off  by  storms.  Nearly  all  of  these  contain 
the  caterpillar  which  has  done  the  girdling,  and  the  branch  soon 
wilts  and  dies.  Though  most  df  the  larvae  desert  the  branch 
within  two  or  three  days  after  it  falls,  the  junior  author  has 
found  several  of  these  shrunken  and  in  a  dying  condition  on  the 
branch,  showing  that  the  insect  cannot  sustain  life  on  the  dead 
wood.  It  is  also  evident  that  very  few  of  those  which  leave  the 
branch  are  able  to  again  find  and  climb  a  large  tree.  On  city 
streets  these  branches  are  usually  gathered  at  once  and  destroyed 
because  of  their  hindrance  to  traffic.  In  parks  it  is  even  more 
necessary  that  this  should  be  done,  as  here  the  insects  can 
easily  leave  the  fallen  branches  and  enter  shrubbery  or  small  trees. 

Remedial  Treatment. 

In  view  of  the  protected  life  led  by  this  insect,  treatment  is 
especially  difficult.     Tunneling  under  the  bark  during  the  greater 


l6      CONNECTICUT    EXPERIMENT    STATION,    BULLETIN    NO.    169. 

part  of  its  life,  it  is  not  affected  by  arsenical  or  contact  sprays. 
The  protracted  period  during  which  it  may  appear  as  a  moth 
hinders  effective  action  against  the  adult.  Isolated  trees  recently 
infested,  and  small  trees  with  smooth  bark,  can  be  saved  by  a 
thorough  inspection  two  or  three  times  a  year,  followed  by  the 
removal  of  badly  infested  branches  and  the  destruction  of  larvae 
found,  either  by  the  injection  of  carbon  disulphide  (bisulphide) 
into  their  burrows  or  the  insertion  of  a  hooked  wire  to  draw  them 
out.     Large  trees  badly  infested  should  be  cut  down  at  once. 

Unfortunately,  this  insect  lives  so  concealed  a  life  as  to  attract 
little  attention  until  it  is  well  distributed  in  a  town  or  city  and 
serious  damage  has  been  done  to  the  trees..  Where  not  already 
present,  all  planting  stock  should  be  bought  from  nurseries  free 
from  this  pest, — probably  in  a  district  not  yet  affected.  A  care- 
ful watch  must  be  kept  for  its  first  appearance,  when,  because 
of  the  inability  of  the  female  to  make  long  flights,  the  removal 
of  the  trees  for  a  couple  of  hundred  feet  around  the  affected 
section  will  form  a  quarantine  that  will  greatly  help  to  keep  it 
in  check.  Special  attention  can  then  be  given  to  all  trees  in  and 
close  to  the  affected  area.  Most  citizens  are  averse  to  having 
trees  removed  from  in  front  of  their  property  until  they  are  very 
far  gone,  but  stern  measures  are  necessary  in  preventing  the 
spread  of  this  insect. 

Electric  Lights.  The  moths  are  attracted  by  the  strong  arc 
lights  used  for  street  lighting,  and  numbers  of  them,  largely 
males,  could  be  secured  in  th^  flying  season  by  sending  men 
around  to  collect  them  from  nine  to  twelve  o'clock  at  night,  or 
by  the  payment  of  a  small  bounty  to  boys,  according  to  the 
quantity  collected.  This  method  of  check,  especially  where 
females  are  secured,  is  of  immense  value,  as  it  is  much  easier 
to  prevent  eggs  being  laid  than  to  find  the  larvae,  which  would 
otherwise  hatch. 

Mr.  J.  W.  Chapman,^^  during  the  month  of  July,  had  placed 
in  the  Harvard  College  yard  three  six  ampere  arc  lights,  without 
globes  or  reflectors.  About  twelve  inches  beneath  each  light  a 
pan  three  inches  deep  and  twenty-four  inches  in  diameter  was 
suspended  by  wires.  The  pan  was  then  half  filled  with  water, 
with  a  thin  film  of  kerosene  on  top.  These  lights  were  run  as 
traps    during   the   first   two    weeks    of    July,    the   insects   being 


THE    LEOPARD    MOTH.  1 7 

attracted  to  the  lights  and  then  falHng  into  the  pan  and  being 
killed  by  the  oil.  In  this  way  279  male  and  58  female  moths  were 
taken.  Undoubtedly  if  the  traps  had  been  placed  during  June, 
when  the  moths  first  began  to  fly,  a  correspondingly  larger  num- 
ber would  have  been  taken. 

Removal  of  Affected  Branches.  Trees  badly  affected  are  best 
removed,  as  the  pruning  of  large  numbers  of  branches  leaves 
only  mutilated  specimens  not  worth  the  cost  of  the  repeated 
inspection  and  treatment  required. 

Pruning  should  be  done  while  the  tree  is  in  foliage,  preferably 
twice  a  year,  once  in  spring  and  once  in  late  summer.  The  num- 
ber, size  and  color  of  the  leaves  is  the  best  guide  as  to  affected 
branches.  The  tendency  is  not  to  remove  many  of  these,  which, 
if  left,  will  probably  die  later  in  the  season,  or  at  least  harbor 
numbers  of  eggs  and  of  the  young  larvae  whose  work  does  not 
yet  show.  All  dead  branches  should  be  removed  at  a  point  well 
below  the  beginning  of  the  green  wood,  so  as  to  be  more  likely 
to  secure  the  insects  doing  the  damage.  Branches  containing 
small  leaves,  leaves  thin  or  yellowish  in  color,  or  those  where  the 
leaves  are  few  and  scattered,  are  sure  to  be  infested  and  should 
be  removed. 

Inspection,  and  Destruction  of  Larvae.  On  large  numbers  of 
trees  over  fifty  feet  in  height,  the  expense  of  this  method  is 
prohibitive,  and  the  difficulty  of  locating  the  insects  renders  it 
impracticable.  Especially  is  this  so  with  elms  of  even  smaller 
size,  because  of  the  rough,  scaly  bark  on  all  but  the  smallest  twigs. 
Also  on  such  trees  the  branches  are  very  numerous,  long,  slender 
and  horizontal,  making  climbing  in  some  places  impossible. 

To  find  out  how  successfully  this  method  could  be  applied  to 
large  elms,  the  junior  author  selected  several  badly  infested  ones, 
sixty  to  eighty  feet  high,  and  had  two  of  his  best  climbers  treat  them 
under  his  personal  inspection,  without  limiting  them  as  to  time. 
Then  live  branches  which  had  thus  been  carefully  examined  were 
cut  from  the  tree  and  the  bark  peeled  with  a  draw  knife,  expos- 
ing all  leopard  moth  galleries.  Less  than  twenty-five  per  cent, 
of  the  larvae  on  the  infested  branches  had  been  secured  while  on 
the  tree.  Also,  Mr.  Chapman,  in  describing  the  experiments  in 
Harvard  College  yard,  states  that  previous  to  placing  the  trap 
lamps,  in  which  over  three  hundred  moths  were  secured,    "the 


1 8       CONNECTICUT    EXPERIMENT    STATION,    BULLETIN    NO.    169. 

yard  had  been  patrolled  since  early  spring  by  three  men,  who 
spent  their  entire  time  searching  out  and  destroying  the  larvae 
and  pupae  of  the  moth."®^  On  smaller  trees,  in  New  Haven, 
especially  of  species  with  smooth  bark,  it  was  found  possible, 
by  a  thorough  inspection,  to  secure  practically  all  of  the  older 
larvae. 

In  East  Orange,  New  Jersey,  where  there  are  few  elms,  and 
the  trees  are,  as  a  rule,  from  ten  to  fifty  feet  in  height,  the  fol- 
lowing method,  carefully  applied  for  three  years,  has  placed  the 
leopard  moth  under  control : — Gangs  of  men,  trained  to  the  work, 
in  August  and  September  of  each  year  look  on  the  ground  and 
sidewalk  under  every  tree  for  the  piles  of  brownish  pellets  and 
sawdust  dropped  by  the  borers.  Carefully  spotting  the  branch 
over  each  pile,  the  man  climbs  the  tree  and,  if  experienced,  can 
locate  nearly  every  hole,  which,  at  that  time,  is  covered  by  the  silk 
web,  when  the  insect  is  either  secured  with  a  wire,  or  carbon 
disulphide  is  injected  from  a  small  oilcan,  and  the  hole  stuffed 
with  putty  or  soap. 

Although  the  burrows  are  usually  well  cleared  of  frass,  allow- 
ing the  fumes  of  the  carbon  disulphide  free  access,  there  may 
be  other  outlets  to  the  burrow,  so  the  method  of  securing  the 
insect  with  a  wire  is  surer.  A  piece  of  No.  i6,  soft,  steel  wire 
is  used,  one  end  being  bent  into  a  very  small  hook,  and  sharpened 
from  time  to  time  by  cutting  the  end  of  the  hook  in  a  slanting 
direction  with  a  pair  of  linesman's  pliers.  Often  the  insect  can- 
not be  reached  without  cutting  the  burrow  open  for  some  distance 
with  a  stout  jackknife,  but  this  is  easily  done,  as  there  is  only 
the  bark  to  cut  through,  and  the  real  injury  is  not  increased.  If 
the  branch  is  found  to  be  nearly  girdled,  it  had  better  be  cut  off. 

In  this  way  the  larger  larvae  (those  in  their  second  summer), 
which,  of  course,  are  found  in  the  larger  branches,  are  destroyed, 
preventing  the  laying  of  eggs  the  following  summer.  The  same 
method  is  followed  out  the  succeeding  fall,  when  the  younger 
larvae,  which,  by  this  time,  have  grown  large  and  come  down  to 
the  larger  branches,  are  also  procured. 

In  high  trees,  the  wind  so  scatters  the  falling  pellets  as  to  make 
it  impossible  to  ascertain  from  their  location  on  the  ground  the 
number  or  location  of  the  insects  in  the  tree. 

Disposal  of  Infested  Wood.  It  is  very  often  not  convenient 
in  large  towns  or  cities  to  burn  the  infested  wood  secured  after 


THE    LEOPARD    MOTH.  1 9 

storms  or  by  the  trimming  and  removal  of  trees.  Often  the  wood 
could  be  utilized  by  people  in  the  vicinity  in  which  it  is  collected, 
or  it  may  be  left  at  some  nearby  public  dump. 

During  the  spring  of  191 1,  the  junior  writer  secured  a  number 
of  branches  broken  off  by  storms,  and  containing  larvae.  The 
borers  remained  in  the  wood  for  a  few  days,  until  the  leaves 
began  to  wilt  and  the  wood  commenced  to  dry,  when  most  of 
them  left  the  branches.  Unable,  however,  to  find  new  green 
branches  to  enter,  they  soon  grew  thin  and  died.  Mr.  Chapman,^^ 
with  older  larvae,  secured  later  in  the  season,  found  that  the  borers 
were  able  to  exist  during  the  winter  in  wood  removed  from  the 
tree  and  to  emerge  as  moths  the  following  spring.  Unless  the 
wood  is  to  be  used  immediately,  or  placed  in  a  dump  where  they 
will  soon  be  buried  by  ashes,  dirt,  etc.,  branches  secured  by  trim- 
ming or  blown  down  by  storms  should  be  burned. 

Care  in  Planting.  Until  some  effective  check  is  found  for 
this  insect,  it  is  best  not  to  plant  too  heavily  those  species  of  trees 
which  are  especially  liable  to  attack.  Species  with  short,  strong 
branches,  covered  with  smooth  bark,  should  be  given  the  prefer- 
ence, being  more  easily  inspected  and  taken  care  of  by  the 
methods  just  given.  Planting  the  young  trees  a  greater  distance 
apart  than  usual,  makes  it  more  difficult  for  the  insect  to  spread 
from  one  tree  to  another. 

In  this  connection,  it  might  be  said  that,  in  Brooklyn,  one  of  the 
first  cities  in  America  to  be  infested,  Mr.  J.  J.  Levison  reports 
the  insect  as  far  less  injurious  than  formerly,  although  no  direct 
measures  have  been  taken  for  its  control,  and  the  junior  author 
has  seen  there  rows  of  elms  and  other  trees  almost  untouched 
by  this  insect. 

Care  of  Trees.  Although  trees  in  good  health  are  not  immune 
to  attack,  many  authorities  claim  that  they  are  less  liable  to  injury 
than  unthrifty  trees.  It  is  certain  that  in  New  Haven  the  great- 
est damage  by  the  leopard  moth  has  been  done  to  trees  on  streets 
where  the  conditions  are  most  adverse  to  tree  life,  and  at  least 
wounds  are  more  easily  healed,  and  recovery  after  attack  is  surer, 
where  the  trees  are  kept  in  a  thrifty  condition. 


20      CONNECTICUT    EXPERIMENT    STATION,    BULLETIN    NO.    169. 

BIBLIOGRAPHY. 


AMERICAN. 


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2  1864     Packard,    A.    S.     Proceedings    Philadelphia    Entomological 

Society,  iii,  p.  390  (N.  A.). 

3  1882     Doll,  J.     Papilio,  vol.  ii,  p.  34. 

4  1888     Graef,  E.  L.     Entomologica  Americana,  vol.  iv,  p.  162. 

5  1889     Angelman,   J.    B.     Entomologica   Americana,   vol.    v,   p.   28 

(Newark,  1887). 

6  Grote,  A.  R.     Entomologica  Americana,  vol.  v,  p.  7. 

7  Smith,  J.  B.     Report  New  Jersey  Agricultural  Experiment 

Station,  p.  279. 

8  1890     Chittenden,  F.  H.     Entomologica  Americana,  vol.  vi,  p.  218 

(note  re  distribution). 

9  Machesney,   C.  P.     Entomologica  Americana,,  vol.  vi,  p.  31 

(Arlington). 

10  Riley,  C.  V.  and  Howard,  L.  O.     Insect  Life,  vol.  ii,  p.  290 

(note  re  Smith's  article  in  Garden  and  Forest). 

11  Smith,  J.  B.     Insect  Life,  vol.  ii,  p.  386  (correction  of  pre- 

ceding). 

12  Smith,  J.  B.     Garden  and  Forest,  vol.  iii,  p.  30. 

13  1891     Southwick,  E.  B.     Report  Entomological  Society  of  Onta- 

rio, xxii,  p.  78  (recent  destruction  in  New  York). 

14  Smith,  J.  B.,  et  al.     Canadian  Entomologist,  vol.  xxiii,  p.  221 

(discussion  at  meeting). 

15  1892     Lintner,  J.  A.     Report  New  York  State  Entomologist,  vol. 

ix,  p.  426  (brief  acct.). 

16  Pike,  N.     Insect  Life,  vol.  iv,  p.  317  (illus.  article). 

17  Riley,  C.  V.  and  Howard,  L.  O.     Insect  Life,  vol.  iv,  p.  77-8 

(notes  of  correction). 

18  Smith,    J.    B.     Canadian    Entomologist,    vol.    xxiv,    p.    136 

(remarks  on  Walker's  citation;    doubts  identity). 

Smith,  J.  B.     Entomological  News,  vol.  iii,  p.  206  (note). 

Southwick,  E.  B.     Insect  Life,  vol.  iv,  p.  61   (note). 

Riley,  C.  V.  and  Howard,  L.  O.  Insect  Life,  vol.  v,  p.  204 
(note  of  correction). 

Neumoegen,  B.  and  Dyar,  H.  G.  Journal  New  York  Ento- 
mological Society,  vol.  ii,  p.  160  (descr.  pyrina). 

23  Riley,  C.  V.  and  Howard,  L.  O.     Insect  Life,  vol.  vi,  p.  40 

(note  on  number  of  eggs). 

24  Riley,  C.  V.  and  Howard,  L.  O.     Insect  Life,  vol.  vi,  p.  ^77 

(note  on  habits). 

25  Smith,  J.  B.     New  Jersey  Agricultural  Experiment  Station, 

Bull.  103,  p.  9. 


19 

20 

21 

1893 

22 

1894 

THE    LEOPARD    MOTH.  2  1 

26  1894     Smith,  J.  B.     Report  New  Jersey  Agricultural   Experiment 

Station,  p.  519  (good  acct.)- 

27  Southwick,   E.  B.     Report  Entomological  Society  Ontario, 

XXV,  p.  107  (recent  destruction  in  New  York). 

28  1895     Smith,  J.   B.     Insect   Life,  vol.  vii,   p.   138    (report  by   Pike 

from  Connecticut). 

29  Southwick,   E.  B.     Insect  Life,  vol.  vii,  p.   136   (mention  of 

injury). 

30  1896     Smith,    J.    B.     Economic    Entomology,    p.    287    (brief    illus. 

acct.). 

31  1897     Smith,  J.  B.     Report  New  Jersey  Agricultural  Experiment 

Station,  p.  397  (mention). 

32  Webster,    F.    M.     vOhio    Agricultural    Experiment    Station 

Bull.  ']'],  p.  48  (illus.  acct.). 

33  1898     Beutenmiiller,    Wm.      Bombycine     Moths    of    Vicinity    of 

New   York,   Bull.   Amer.    Museum    Natural    History,   vol. 
x,  p.  445  (descr.  and  note,  illus.). 

34  Felt,  E.  P.     Report  of  Commissioners  of  Fisheries,   Game 

and  Forests,  iv,  p.  16  (illus.  acct.). 

35  Smith,  J.  B.     Report  New  Jersey  Agricultural  Experiment 

Station,  p.  385  (mention). 

36  1899     Felt,   E.  P.     New  York  State  Museum,  vol.  vi.   No.  o.y,  p. 

50  (brief  acct.,  illus.). 

37  Smith,  J.  B.     Insects  of  New  Jersey,  Suppl.   Report  N.  J. 

Board  of  Agriculture,  p.  497  (brief  acct.,  illus.). 

38  Smith,  J.  B.     Report  New  Jersey  Agricultural  Experiment 

Station,  p.  445  (mention). 

39  1900     Britton,  W.  E.,  et  al.     Connecticut  Agricultural  Experiment 

Station  Bull.  131,  p.  13   (mention). 

40  Felt,  E.  P.     New  York  State  Museum,  vol.  viii.  No.  zi,  P- 

23   (note,  illus.). 

41  MacCartnej^    B.    F.     Report    Pennsylvania    Department    of 

Agriculture,  p.  94  (brief  illus.  acct.). 

42  1901     Felt,    E.   P.     Report   New   York   State    Entomologist,   xvii, 

p.  745  (occurrence  at  Newark,  N.  Y.). 

43  Smith,  J.  B.     Report  New  Jersey  Agricultural  Experiment 

Station,  p.  480  (mention;   not  so  destructive). 

44  1903     Gibson,  A.     Report  Entomological  Society  Ontario,  xxxiv, 

p.  61  (mention). 

45  Holland,  W.  J.     Moth  Book,  p.  zi^  (illus.  acct.). 

46  1904     Doll,  J.     Entomological  News,  vol.  xv,  p.  no. 

47  1905     Felt,   E.  P.     Insects  xA^fTecting  Park  and  Woodland  Trees, 

vol.  i,  p.  75  (full  acct.,  illus.). 

48  Smith,  J.  B.     New  Jersey  Agricultural  Experiment  Station 

Bull.  181,  p.  29  (brief  acct.). 

49  1907     Fernald,  C.  H.  and  H.  T.     Report  Massachusetts  Agricul- 

tural Experiment  Station,  p.  155  (short  note,  damage  near 
Boston). 


2  2      CONNECTICUT    EXPERIMENT    STATION,    BULLETIN    NO.    169. 

50  1907     Frost,  C.  A.     Psyche,  vol.  xiv,  p.  63   (appearance  in  Mass. 

in  1903). 

51  1908     Britton,    W.    E.     Report    Connecticut   Agricultural    Experi- 

ment Station,  p.  847  (presence  in  Conn.). 

52  Smith,    J.    B.      Report    New    Jersey    Forest    Commission, 

p.  89. 

53  Smith,    J.    B.      Report    New    Jersey    Agricultural    Experi- 

ment Station,  p.  315  (mention). 

54  1909     Britton,    W,    E.     Report    Connecticut    Agricultural    Experi- 

ment Station,  p.  356  (acct.). 

55  Fernakl,  C.  H.  and  H.  T.     Report  Massachusetts  Agricul- 

tural Experiment  Station,  part  2,  p.  72  (mention). 

56  Howard,   L.   O.   and    Chittenden,    F.    H.      Bureau   of   Ento- 

mology  Circular    109    (full   acct.,   illus.). 

57  Reiff,  Wm.     Psyche,  vol.  xvi,  p.  28  (larva  in  oak). 

58  Smith,  J.  B.     Insects  of  New  Jersey,  rev.  ed..  Report  New 

Jersey  State  Museum,  p.  516  (illus.  acct.). 

59  1910     Britton,    W.    E.     Journal    Economic    Entomology,    vol.    iii, 

p.  436   (mention), 

60  Britton,   W.    E.     Report    Connecticut   Agricultural    Experi- 

ment Station,  p.  664  (mention). 

61  191 1     Britton,    W.    E.     Journal    Economic    Entomology,    vol.    iv, 

p.  298  (on  nursery  stock,  illus.). 

62  Solotarofif,  Wm.     Shade  Trees  in  Towns  and  Cities,  p.  182 

(illus.   acct.). 

63  Chapman,   J.    W.     The    Leopard    Moth    and   other    Insects 

Injurious  to  Shade  Trees  in  the  Vicinity  of  Boston.     Bus- 
sey  Institution,  Harvard  University  (full  acct.). 


EUROPEAN. 


The  authors  have  made  no  attempt  to  give  a  complete  list  of  Euro- 
pean writings  on  the  leopard  moth.  A  few  are  here  cited  from  works 
on  hand  to  indicate  the  status  of  the  insect  as  a  pest  in  Europe. 

64  1840     Kollar,  V.     Insects  Injurious  to  Gardeners,  Farmers,  etc., 

p.  207  (brief  acct.). 

65  1854-66     Walker,  F.     List  of  Specimens  of  Lepidopterous  Insects 

in  the  Collection  of  the  British  Museum. 

66  1873     Wood,  J.  G.     Insects  at  Home,  p.  428  (brief  illus.  acct.). 

67  1874     Kaltenbach,  J.  H.     Die  Pflanzenfeinde,  pp.  73,  184,  429,  548, 

774  (mention  of  food  plants). 

68  1890     Ormerod,  E.  A.     Manual  of  Injurious  Insects,  p.  320  (brief 

illus.  acct.). 

69  1892     Ormerod,   E.  A.     Text  Book  of  Agricultural   Entomology, 

p.  132  (mention,  illus.). 

70  1895     Judeich    (J.   F.)-Nitsche    (H.)      Forstinsektenkunde,   p.   773 

(illus.  acct.). 


THE    LEOPARD    MOTH.  23 

71  1895     Schlicli,  Wm.     Manual  of  Forestry,  vol.  iv,  p.  264   (descr. 

note  about  injury  and  food  plants). 

72  1897     Eckstein,  K.     Forstliche  Zoologie,  p.  479  (brief  acct.). 

73  1898     Ormerod,   E.  A.     Hand  Book  of  Orchard  and  Bush   Fruit 

Insects,  p.   132   (illus.  acct.). 

74  1901     Sharp,    D.     Cambridge    Natural    History,    vol.    vi,    p.    395 

(mention). 

75  1903     Henry,  E.     Atlas  d'Entomologie  Forestiere,  p.  29  (illus.). 

76  1904     Theobald,   F.   V.     Report   on   Economic   Zoology,   ii,   p.   30 

(note). 

77  1905     MacDougall,    R.    S.     Journal    Board    of   Agriculture    (Lon- 

don), 12,  No.  2,  p.  115.     Abstract  Expr.  Sta.  Record,  vol. 
xvii,  p.  1092  (remedial  treatment). 

78  1908     Gillanders,  A.  T.     Forest   Entomology,  p.  247    (brief  illus. 

acct.;    sycamore,  hawthorn). 

79  Lesne,    P.     Compt.    Rend.    Academy    Science    (Paris)    146, 

P-  493  (great  damage  to  cork  oak  in  Algeria). 

80  Theobald,  F.  V.     Report  on  Economic  Zoology,  p.  24  (brief 

note). 

81  1909     South,  R.     The  Moths  of  the  British  Isles,  p.  348. 

82  Theobald,  F.  V.     Insect  Pests  of  Fruit,  p.  46  (illus.  acct.). 

83  Theobald,  F.  V.     Report  on  Economic  Zoology,  p.  29  (brief 

note,  illus.). 

84  191 1     Lesne,    P.     Compt.    Rend.    Academy    Science,    152,   p.    1269. 

Abstract    Expt.    Sta.   Record,   vol.   xxv,   p.   464    (larvae   in 
cork  oak). 


24      CONNECTICUT    EXPERIMENT    STATION,    BULLETIN    NO.    169. 

SUMMARY. 

The  leopard  moth  occurs  in  Europe  and  parts  of  Asia  and  Africa, 
and  was  probably  accidentally  introduced  into  this  country  from 
Europe  more  than  thirty  years  ago,  being  first  noticed  at  Hoboken, 
N.  J.,  and  later  spreading  toward  the  north  and  east  along  the  coast. 
At  the  present  time  it  is  found  from  Asbury,  N.  J.,  to  Lawrence, 
Mass.,  but  has  not  been  taken  more  than  twenty-five  miles  inland. 

The  larvae  or  caterpillars  cause  great  damage  to  nearly  all  kinds 
of  shade  trees  by  boring  in  the  branches  just  under  the  bark  and 
cutting  large  galleries,  often  across  the  grain,  thus  girdling  them. 
Dead  branches  extending  above  the  mass  of  foliage  in  the  tree-tops 
are  a  sign  of  attack,  and  many  twigs  will  be  broken  off  or  wither 
during  the  summer.  The  pest  has  been  especially  destructive  to  elm 
and  silver  maple  trees  in  the  coast  cities  and  towns  of  Connecticut, 
but  is  not  so  abundant  in  the  open  country.  It  has  caused  much 
damage  also  in  the  cities  of  New  Jersey,  New  York  City,  Providence, 
Cambridge  and  Boston. 

The  adult  moths  are  dirty  white,  with  semitransparent  wings 
marked  with  metallic  blue  dots.  These  have  an  expanse  of  one  and 
three-fourths  inches  in  the  male  to  two  and  one-half  inches  in  the 
female.  The  larva  is  yellow  or  dirty  white,  marked  with  brown  or 
black  dots,  and  about  two  inches  long.     See  illustrations. 

The  moths  appear  about  July  ist,  the  males  being  very  common 
around  electric  lights,  and  the  females  lay  eggs  singly  or  in  groups 
of  two,  three  or  four,  in  the  crevices  of  the  bark  or  near  the  buds. 
The  larvae,  hatching  in  a  few  days,  begin  to  tunnel  in  the  twigs,  and 
by  the  end  of  the  season  are  about  one  inch  in  length.  They  leave 
the  small  branches  and  crawl  over  the  bark  to  enter  larger  ones, 
cutting  large  galleries  in  them  and  expelling  the  frass  through  round 
holes,  which  they  soon  close  with  silk  webs.  During  October  the 
borers  go  deeper  into  the  wood,  and  remain  through  the  winter  two 
inches  or  more  beneath  the  bark.  They  pupate  in  their  burrows  the 
second  spring,  and  before  the  moth  emerges  the  pupa  works  itself 
partly  out  of  the  opening,  and  the  adult  flies  away,  leaving  the  empty 
case  protruding  from  the  burrow. 

There  are  few  natural  checks,  only  one  parasite  being  known  in  this 
country  and  four  in  Europe.  It  is  believed,  however,  that  certain 
birds,  especially  woodpeckers,  prevent  the  spread  of  the  leopard  moth 
in  the  open  country.  Many  larvae  are  doubtless  killed  by  the  break- 
ing off  of  the  branches,  which  in  cities  are  carted  away  and  destroyed. 
Removing  infested  branches;  injecting  carbon  disulphide  (bisul- 
phide) into  the  burrows,  and  stopping  the  opening;  probing  with  a 
hooked  wire  for  the  larva;    are  some  of  the  methods  of  control. 

Planting  species  of  trees  not  badly  infested,  like  oaks,  honey  locust 
and  sycamore,  and  especially  those  kinds  that  do  not  grow  very 
large,  and  have  a  smooth  bark;  placing  trees  further  apart,  so  that 
the  larvae  cannot  easily  crawl  from  one  to  the  other;  and  keeping 
the  trees  well  nourished  and  vigorous,  are  the  chief  preventive 
measures. 


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